This invention relates to a pin lock designed to act as a coupling between a drive shaft and a driven shaft. Devices which perform this general function are known in the prior art. In this vein, the following prior art is known to applicant:
U.S. Pat. No. 364,503 to Fenner which discloses a universal joint including cube-like block C which fits within receptacle B. A pin E passes through receptacle B, block C and a pin D connected to fork A to couple fork A to receptacle B. Since this device requires an intermediary block C and, further, since the coupled halves are both fork-like, applicant's invention is believed distinct therefrom.
U.S. Pat. No. 693,577 to Vivinus which discloses a further universal joint including a cylindrical receptacle a, a knob-like rod b and a pin d, e which extends through holes formed in receptacle a and which is retained in position by transverse locking pins f. This patent is believed distinct from applicant's invention in that the knob b does not conform to receptacle a and, further, since the pin d, e extends through the knob b.
U.S. Pat. No. 2,211,164 to Rippenbein which discloses a coupling between a receptacle 24 and a rectangular cross-section rod 25 which are retained together by a sleeve 26 which is tightened in place by a screw 27. The provision of a separate piece of structure 26, 27 to retain two members 24, 25 together is believed to distinguish applicant's invention from this patent since, in applicant's invention, the receptacle and pin provide the sole retention means.
U.S. Pat. No. 3,285,668 to Fearon which discloses a receptacle 10 secured to a cutting device and a cutter bit 15 including a rectangular cross-section shank 16 which fits into receptacle 10 and is retained therein by transverse pin 30. Applicant's invention is believed distinct from this patent in that (1) the torque transmitted in the patented device is not rotary and (2) the shank 16 requires a groove 36 to mesh with pin 30.
U.S. Pat. No. 3,606,407, which discloses a shaft coupling including receptacle 33 of cubical dimensions, cubical shaft end key 30 which fits into receptacle 33, half-cylindrical retainers 42, 44 and set screw 58. Applicant's invention is believed distinct from the patented device since applicant's pin retainer is less cumbersome than patentee's half-cylinders and set screw.
U.S. Pat. No. 3,867,050 to Pitner which shows, for example in FIGS. 1 and 2, a substantially rectangular cross-section shaft 3 placed in a corresponding receptacle 6 and retained therein with bolt 21 tightened by nut 22. The requirement of tightening the coupling is believed to distinguish this patent from applicant's invention.
Applicant is further aware of U.S. Pat. Nos. 2,355,781 to Cardinal and 2,869,842 to Schmidt which are believed less relevant than the above discussed patents.